Radiant Cooling Technology – A Sustainable Building Solution

In regions with tropical climates, a building's air conditioning and ventilation can be responsible for over 50% of its total energy usage. As the demand for cooling continues to climb—spurred by economic growth in developing nations and intensified by climate change—it's essential we pivot to more eco-friendly and energy-efficient cooling methods. One such solution that stands out is Radiant Cooling Technology.

This advanced method not only substantially cuts energy consumption but also enhances indoor air quality, ensuring a more comfortable environment for occupants.

Understanding Radiant Cooling System

Radiant cooling operates primarily on principles of radiation and convection heat transfer. Here's a simplified breakdown (See Fig. 1 for reference):

  1. Sensible Cooling: Chilled to about 14°C, water circulates through the system. After absorbing heat from the environment, the warmer return water is then sent back to the chiller at a temperature of around 19°C.
  2. Humidity and Ventilation: Fresh, dehumidified air is introduced to the area at roughly 12°C to regulate humidity levels and ensure proper ventilation.
  3. Efficient Cooling: The surfaces, usually ceilings, through which the chilled water flows, are kept at a temperature of 18-19°C. This direct cooling mechanism efficiently cools the room. Interestingly, about half of the heat transfer is radiative, while the other half is convective for these cooled surfaces.

Essential components of Radiant Cooling System

1. PEXa Pipes: Specialized PEXa pipes are created from a high-grade plastic raw material, HD polyethylene. Manufacturers of these pipes often claim a lifespan of 100 years, making them optimal for systems meant to be embedded and remain in place for extended periods. These pipes serve as the radiant surface and can be strategically concealed within various parts of a building (Fig. 2).

Depending on their placement, the radiant cooling system can take various forms: (a) radiant slab cooling - pipes embedded inside a slab during construction (Fig. 3); (b) radiant floor cooling - pipes embedded inside floor screed (Fig. 4); (c) radiant ceiling cooling - pipes embedded inside the false ceiling.

2. Centralized Radiant Cooling Plant: This plant is the heart of the radiant cooling system. It typically features, (1) a medium-temperature chiller circuit that supplies chilled water at 14°C to the radiant cooling surface and (2) a separate low-temperature chiller circuit supplying chilled water at 6.6°C for a dehumidification coil inside the treated fresh air unit so that the dehumidified ventilation air can be supplied to the zone below 12°C. 

3. Cold/Chilled Water Source: Radiant systems can harness chilled water from a variety of sources. Some of the prevalent methods include:

The Pros and Cons of Radiant Cooling Systems

1. Benefits of Radiant Cooling Systems:

    Energy efficiency-

     Enhanced Indoor Air Quality-

2. Challenges of Radiant Cooling Systems:

The increasing number of installations, with over 60 in India alone, underscores the system's potential. It's not merely a novelty but a proven technology gaining traction in modern building designs. One notable example of its application is at the Tulah Wellness Centre in Calicut, Kerala, India.


Renew Consulting Engineers (Pvt) Ltd

No. 302, First floor, HRBR layout,

1st block, Kalyan Nagar, Bengaluru – 560043, Karnataka, India


Mr. Jabish Joy (jabish.joy@renewconsulting.in § +91 7849005002)

Mr. Nandish P (nandish.p@reneAwconsulting.in § +91 9986677717)

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